Dispensing gun devices which eject a viscous material from a disposable cylindrical cartridge in response to a pressurized fluid are known in the art. Stamets et al U.S. Pat. No. 3,712,516, Collar U.S. Pat. No. 3,237,814 and Detrie et al Pat. No. 2,838,210 illustrate three such devices known in the prior art. The devices in the above-mentioned Collar and Detrie et al patents are operable in response to pressurized air being introduced into a chamber behind the piston-like rear wall of the cartridge. The Stamets et al patent is operable only in response to pressurized water. It is our desire to make a dispensing gun capable of dispensing a viscous material in response to the introduction of a pressurized fluid to the rear side of the piston-like rear wall of the cartridge more convenient to usage with any available pressurized fluid, be it a source of pressurized gas or a source of pressurized liquid.
Accordingly, the objects of this invention include:
1. To provide a fluid operated dispensing gun for dispensing a viscous material from a disposable cylindrical cartridge in response to either pressurized air or pressurized liquid being introduced to the rear side of the piston-like rear wall of the disposable cartridge;
2. To provide separate manually operated valves for (a) turning the flow of fluid to the rear side of the piston-like rear wall of the disposable cartridge on or off and (b) controlling the rate of flow of the pressurized fluid to the rear side of the piston-like rear wall of the disposable cartridge;
3. To provide an inflatable bladder member mountable in the rear end of the barrel and being adapted to inflate into the interior of the disposable cartridge on the rear side of the piston-like rear wall to urge the piston-like rear wall toward the outlet of the cartridge to thereby urge viscous material out through the cartridge outlet, the inflatable member functioning to prevent the pressurized fluid from leaking around the periphery of the piston-like rear wall of the disposable cartridge and becoming mixed with the viscous material;
4. To provide a fluid operated dispensing gun, as aforesaid, which can be used by connecting same to a convenient garden hose connected to a conventional water supply system in a home; and
5. To provide a fluid operated dispensing gun, as aforesaid, which can be used by connecting same to a convenient source of pressurized air.